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Luminescent metal-organic frameworks (LMOFs) with diverse structural features and promising fluorescence-based applications have attracted wide attention in the past two decades. In this work, a LMOF with the formula [Ca4(tcbpe-F)2(H2O)3] (1, LMOF-411) has been constructed from calcium (Ca) and 1,1,2,2-tetrakis(4-(4-carboxyphenyl)phenyl)ethene (H4tcbpe-F). Compound 1 features a three-dimensional framework with a 10-nodal net topology. Due to the relatively high hydration energy of Ca2+, compound 1 readily transforms into a new phase formulated as [Ca(H2tcbpe-F)(H2O)2] (1') upon exposure to water. Combining experimental characterization and theoretical calculations, we elucidated the mechanism of H2O-induced phase transition from 1 to 1'. Notably, the water induced phase transformation can be detected visibly from the change in luminescence, which originates from the fluorescent linker. Compound 1 emits green light (λ em = 490 nm) under UV excitation, while compound 1' emits bright yellow light (λ em = 550 nm) under blue excitation (450 nm). Compound 1' represents the first Ca based LMOF yellow phosphor and its luminescence quantum yield reaches 68%. It can be coated directly onto a commercial blue light-emitting-diode (LED) chip to fabricate a white LED (WLED).

Stimuli-responsive inorganic–organic hybrid metal halides (IOMHs) have shown great potential in sensing, information encryption and anti-counterfeiting, etc. However, the stimuli-responsive behavior based on the regulation of the functional groups in organic species is still blank in IOMHs. Herein, three zero-dimensional (0-D) antimony-based IOMHs with different functional groups in the organic cations are reported, namely [AOEMIm]3SbCl6 (1, AOEMIm = 1-acetoxyethyl-3 methylimidazolium), [HOOCMMIm]3SbCl6·3(OOCMMIm) (2, HOOCMMIm = 1-carboxymethyl-3-methylimidazolium) and [HOOCMMIm]3SbCl6 (3). Photophysical characterizations show that 1, 2 and 3 exhibit typical self-trapped exciton triplet broadband emission, peaking at 610, 510 and 525 nm under excitation of 365 nm, 375 nm and 345 nm, respectively. Under the H2O stimulation, the organic groups in the crystal structures undergo a mutual transformation, that is, from acetoxyethyl or carboxyl to a mixture of carboxyl and deprotonated carboxyl. Accordingly, the organic group switching is accompanied by a solid–solid transformation from 1 or 2 to 3 crystals. The intrinsic mechanism for the phase transition is expounded as well. Due to the obvious luminescence change from yellow-green emission (3) to green emission (2), 3 is further applied in the detection of trace water in organic solvents. The water detection limit in tetrahydrofuran (THF) is as low as 0.3% v/v. This study provides a new avenue for the construction of stimuli-responsive IOMHs. [ABSTRACT FROM AUTHOR]

A new layered metal sulfide, namely (C6H15N3)1.3(NH4)1.5H1.5In3SnS8 (1, C6H15N3 = N-(2-aminoethyl) piperazine), has been solvothermally synthesized and characterized. Compound 1 crystallizes in the monoclinic space group C2/c. Its structure features a two-dimensional layer of {In3SnS8}n3n− with the (4,4) topology net, which is formed by interlinking supertetrahedral T2 clusters as secondary building units. Band structure calculations revealed that 1 had a band gap of 2.7 eV. The photoelectric response of 1 showed steady and reversible on/off cycles with an "on" state of 121.13 nA cm−2. Moreover, the activation of 1 by replacing the sluggish organic cations with harder K+ ions endowed the material with improved adsorption performances for Sr2+ ions from aqueous solutions. [ABSTRACT FROM AUTHOR]

C6H8CdN2O7, monoclinic, P21/c (no. 14), a = 7.3428(15) Å, b = 11.272(2) Å, c = 12.764(4) Å, β = 118.73(2)°, V = 926.4(4) Å3, Z = 4, Rgt(F) = 0.0261, wRref(F2) = 0.0609, T = 293(2) K.

With the rapid development of white LEDs, the research of new and efficient white light emitting materials has attracted increasing attention. Zero dimensional (0D) organic–inorganic hybrid metal halide perovskites with superior luminescent property are promising candidates for LED application, due to their abundant and tailorable structure. Herein, [(CH3)3S]2SnCl6·H2O is synthesized as a host for dopant ions Bi3+ and Sb3+. The Sb3+ doped, or Bi3+/Sb3+ co-doped, [(CH3)3S]2SnCl6·H2O has a tunable optical emission spectrum by means of varying dopant ratio and excitation wavelength. As a result, we can achieve single-phase materials suitable for emission ranging from cold white light to warm white light. The intrinsic mechanism is examined in this work, to clarify the dopant effect on the optical properties. The high stability of title crystalline material, against water, oxygen and heat, makes it promising for further application. [ABSTRACT FROM AUTHOR]

Three new group IIIA metal phosphate–oxalate (MPO) compounds, namely [(CH3)2NH2]2[M2(HPO4)2(H2PO4)2(C2O4)] (M = Al (1), Ga (2)) and [(CH3)2NH2]2[In2(HPO4)2(H2PO4)2(C2O4)]·H2O (3), have been synthesized. Their crystal structures feature an anionic layer with the sql topology net. In particular, 1 displays a proton conductivity (σ) of 9.09 × 10−3 S cm−1 at 85 °C and under 98% relative humidity, which is the highest among MPOs. This study not only endows the main group metal-based MPO family with new members, but also contributes to further understanding of the structure-directing roles of amines and provides a feasible idea for improving the proton conductivity of MPOs. [ABSTRACT FROM AUTHOR]

Two isostructural Co(Cd)-antimony-oxo tartrate cluster-based compounds with a one-dimensional (1-D) belt-like structure, namely H9.2[Co(H2O)6]{M0.5(H2O)3.5{M′(H2O)4[SbVO6[Co4.2(H2O)5Sb III6 (μ3-O)2(tta)6]]}}2·nH2O (M = Co, M′ = Co, n = 9 (1); M = Cd0.39/Co0.61, M′ = Cd0.24/Co0.76, n = 7 (2); H4tta = tartaric acid), have been synthesized by solvothermal methods. It is noteworthy that the relatively rare mixed-valence Sb(III , V) exists in the structures. The anionic clusters in both compounds appear to be in a sandwich configuration; the top and bottom layers are based on {Sb3(μ3-O)(tta)3} brackets, and the intermediate layer is occupied by {SbVO6[Co4.2(H2O)5]}. The title compounds have been characterized by single-crystal X-ray diffraction, powder X-ray diffraction, elemental analyses, thermogravimetric analyses, and UV-Vis spectroscopy. We chose compound 2 as a representative to test its proton conductivity, and the results show that the conductivity can reach 1.42 × 10−3 S cm−1 at 85 °C under 98% relative humidity. [ABSTRACT FROM AUTHOR]